Malaria prophylaxis

See related separate articles Malaria and Malaria in pregnancy.

The ABCD of malaria prophylaxis:¹

• Awareness of the risk of malaria.

• Bites - reducing likelihood of bites from anopheline mosquitoes.

• Chemoprophylaxis.

• Diagnosis and prompt treatment to prevent complications.

No single measure is 100% effective but the combination of measures will significantly lessen the risk.

Epidemiology¹

• UKHSA figures for 2023 showed:

  • There were 2,106 cases of reported malaria in the UK, 93% of which were in England. This is the highest total since 2001.

  • There were six deaths from malaria, which is the same as the average from 2014 to 2023; the median age of those who died was 52.

  • 85% of cases were due to Plasmodium falciparum, which causes the most serious disease; the others were due to P. vivax, P. ovale, P. malariae, or mixed infection.

  • Almost half of all cases were seen in London.

  • 72% were UK residents travelling abroad with the rest being new arrivals to the UK.

Awareness of risk¹

Risk assessment should include:

• Geographical destination - the website TravelHealthPro (commissioned by the UK Health Security Agency, UKHSA) is very helpful.²

• Travellers to remote locations should seek expert advice, as risks may be different from a tourist going to a resort.

• The current highest-risk areas are Africa, South and Central America, Asia, and the Middle East. Four countries in Africa account for almost half of all cases globally (Nigeria, Democratic Republic of the Congo, Uganda and Mozambique).

• Type of travel: there is higher risk for tourists travelling outside urban areas to countryside or game parks, business travellers to downtown offices, overland backpackers, those undertaking prolonged travel, and expatriates intending to reside in the area.

• High-risk categories include pregnant women, asplenic patients, young children, and those with HIV/AIDS.³

Avoidance of bites¹

• Avoidance of bites is important, particularly because chemoprophylaxis is never 100% effective, problems of drug resistance are increasing and there is evidence that the risk of contracting malaria is proportional to number of bites. Bites occur mainly between dusk and dawn, although some species of mosquito which can transmit dengue fever bite during the day also.

• Keep the arms and legs covered after sunset.

• There is good evidence that covering exposed limbs with repellent containing diethyltoluamide (DEET) is effective. When sunscreen is applied, it should be used before DEET. It is suitable for all adults and for children over the age of 2 months. Various strengths are available. 50% is the most effective. There is no evidence of serious toxicity, even in small children and pregnant women. Some patients develop an allergic or irritant response, in which case lower strengths are available. Preparations weaker than 50% will require more frequent application. There is no evidence of effectiveness of strengths of less than 20%.

• Picaridin (KBR3023) (1-piperidinecarboxylic acid, 2-(2-hydroxyethyl)-,1-methylpropylester) is reported to have repellent properties comparable with those of DEET. If a traveller elects to use picaridin for mosquito bite prevention, a 20% preparation should be used. There is evidence that picaridin is an appropriate option for patients who develop contact dermatitis with DEET.⁴

• Permethrin is a useful insecticide to spray on clothing. Pre-treated clothing is available for purchase.

• Patients should be advised to sleep in air-conditioned rooms if possible, or screened accommodation.

• Use of sprays with knockdown insecticide or electrical pyrethroid vapourisers every evening after dusk is recommended.

• Insecticide-treated nets should be used by those sleeping outdoors or in unscreened rooms. The effectiveness is about 50%. Pyrethroid-impregnated nets improve protection and should be re-impregnated every 6-12 months, although resistance is becoming a problem. The search for newer, more effective insecticides is ongoing.

Chemoprophylaxis¹

• Reinforce that prophylaxis is not absolute, breakthrough infection can occur, and that risk avoidance is still necessary.

• Consider the risks versus the benefits of every option, including factors such as how long before the journey the patient has consulted and how long before travel a regimen needs to be started.

• Discuss possible side-effects, and recommend seeking advice if there is any concern or medication has to be stopped.

• Doxycycline should not be used in children or in breastfeeding women.

• Advise the patient to seek advice from a specialist travel clinic if they have a complex medical history which means that you don't feel safe to advise.

• Look at a reputable source such as TravelHealthPro or the UKHSA guidelines ¹for advice on specific areas and regimens; do not use this leaflet as your entire reference as it is not updated regularly enough to be reliable. The table below contains some basic information only about the relevant options and should not be seen as exhaustive; which drug works in which area has deliberately been omitted, as resistance changes rapidly.

• Where a journey requires two regimes, use the regime for the higher-risk area for the whole journey. Warn settled immigrants or long-term visitors to the UK that they may have lost some of their immunity and that previously uninfected areas may now be malarious.

• Malaria chemoprophylaxis is not prescribable on the NHS.

Standby therapy¹

• The UKHSA recommends that those travelling to an area where medical attention is unlikely to be available within 24 hours take emergency treatment for malaria, as well as using chemoprophylaxis.

• The patient must be carefully counselled regarding presenting symptoms, indications and safe use of drugs.

• Treatment should be started if the patient is unable to seek medical help within 24 hours of a fever. An antipyretic such as paracetamol should be taken to reduce fever, as this also reduces the risk of vomiting antimalarial drugs. Once the fever is under control, standby therapy should be commenced. Other preventative measures should be continued.

• The standard treatment course should be completed and antimalarial chemoprophylaxis commenced one week after taking the first treatment dose, except in the case of mefloquine prophylaxis, which should be resumed at least twelve hours after the last treatment dose if quinine was used for standby treatment.

• A second full treatment dose of the antimalarial medication should be taken if vomiting occurs within 30 minutes of taking it (half dose if vomiting occurs after 30-60 minutes).

• The drug used for emergency standby treatment should differ from that used for chemoprophylaxis, both to minimise drug toxicity and due to concerns over drug resistance.

• Warn the patient concerning the adverse reactions of quinine - for example, tinnitus, headache, flushed skin, nausea.

• Patients should be advised not to buy antimalarial drugs over the internet, as the sale of counterfeit products has been reported.

• Standby treatment would generally be given by a private travel clinic, rather than in primary care.

Chemoprophylaxis for long-term travellers¹

Seek specialist advice, especially if there are clinical reasons to extend use beyond evidence-based limits. Long-term travellers are defined as those travelling through or visiting malaria-endemic countries for over six months. As for short-term prophylaxis, a risk assessment should be done which includes risk of malaria, adverse events profile, compliance, and efficacy.

Diagnosis and prompt treatment

Advise patients regarding symptoms of malaria, to report any illness within three months of return, to make their doctor aware of history of malaria exposure and to monitor for symptoms of malaria for up to one year after travel.

Special situations¹

Epilepsy

• Chloroquine and mefloquine are unsuitable.

• Doxycycline or atovaquone/proguanil can be used, but doxycycline should be avoided with phenytoin, carbamazepine, and barbiturates.

• In theory, doxycycline can reduce the plasma concentration of anticonvulsants but there is no evidence that this happens in practice and an increase in dosage of anticonvulsants is not recommended.

Asplenia and severe splenic dysfunction

These patients are at high risk of severe malaria. If travel is unavoidable, take rigorous precautions and use drugs that give good protection.

Renal impairment

• Avoid or reduce the dosage of proguanil, as it is excreted by the kidneys.

• Avoid atovaquone/proguanil in patients with low creatinine clearance (less than 30 ml/minute).

• Chloroquine only needs dosage reduction in severe renal impairment.

• Mefloquine and doxycycline can be used in normal dosage.

Liver impairment

• Severe impairment - specialist advice should be sought. Doxycycline can be used, according to experts in the field (and despite BNF warnings about tetracycline use in liver disease in general) because the mechanism of excretion minimises the metabolic risk. Atovaquone/proguanil can be used and the manufacturers do not recommend any particular precautions or dosage adjustment.

• Moderate impairment - doxycycline, proguanil, or atovaquone/proguanil may be used.

• Mild impairment - chloroquine, proguanil, atovaquone/proguanil or doxycycline may be used.